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/*
* Copyright (C) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* max1363_ring.c
*/
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/i2c.h>
#include "../iio.h"
#include "../ring_generic.h"
#include "../ring_sw.h"
#include "../trigger.h"
#include "../sysfs.h"
#include "max1363.h"
ssize_t max1363_scan_from_ring(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
struct max1363_state *info = dev_info->dev_data;
int i, ret, len = 0;
char *ring_data;
ring_data = kmalloc(info->current_mode->numvals*2, GFP_KERNEL);
if (ring_data == NULL) {
ret = -ENOMEM;
goto error_ret;
}
ret = dev_info->ring->access.read_last(dev_info->ring, ring_data);
if (ret)
goto error_free_ring_data;
len += sprintf(buf+len, "ring ");
for (i = 0; i < info->current_mode->numvals; i++)
len += sprintf(buf + len, "%d ",
((int)(ring_data[i*2 + 0] & 0x0F) << 8)
+ ((int)(ring_data[i*2 + 1])));
len += sprintf(buf + len, "\n");
kfree(ring_data);
return len;
error_free_ring_data:
kfree(ring_data);
error_ret:
return ret;
}
/**
* max1363_ring_preenable() setup the parameters of the ring before enabling
*
* The complex nature of the setting of the nuber of bytes per datum is due
* to this driver currently ensuring that the timestamp is stored at an 8
* byte boundary.
**/
static int max1363_ring_preenable(struct iio_dev *indio_dev)
{
struct max1363_state *st = indio_dev->dev_data;
size_t d_size;
if (indio_dev->ring->access.set_bpd) {
d_size = st->current_mode->numvals*2 + sizeof(s64);
if (d_size % 8)
d_size += 8 - (d_size % 8);
indio_dev->ring->access.set_bpd(indio_dev->ring, d_size);
}
return 0;
}
/**
* max1363_ring_postenable() typical ring post enable
*
* Only not moved into the core for the hardware ring buffer cases
* that are more sophisticated.
**/
static int max1363_ring_postenable(struct iio_dev *indio_dev)
{
if (indio_dev->trig == NULL)
return 0;
return iio_trigger_attach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
/**
* max1363_ring_predisable() runs just prior to ring buffer being disabled
*
* Typical predisable function which ensures that no trigger events can
* occur before we disable the ring buffer (and hence would have no idea
* what to do with them)
**/
static int max1363_ring_predisable(struct iio_dev *indio_dev)
{
if (indio_dev->trig)
return iio_trigger_dettach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
else
return 0;
}
/**
* max1363_poll_func_th() th of trigger launched polling to ring buffer
*
* As sampling only occurs on i2c comms occuring, leave timestamping until
* then. Some triggers will generate their own time stamp. Currently
* there is no way of notifying them when no one cares.
**/
void max1363_poll_func_th(struct iio_dev *indio_dev)
{
struct max1363_state *st = indio_dev->dev_data;
schedule_work(&st->poll_work);
return;
}
/**
* max1363_poll_bh_to_ring() bh of trigger launched polling to ring buffer
* @work_s: the work struct through which this was scheduled
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
* I think the one copy of this at a time was to avoid problems if the
* trigger was set far too high and the reads then locked up the computer.
**/
static void max1363_poll_bh_to_ring(struct work_struct *work_s)
{
struct max1363_state *st = container_of(work_s, struct max1363_state,
poll_work);
struct iio_dev *indio_dev = st->indio_dev;
struct iio_sw_ring_buffer *ring = iio_to_sw_ring(indio_dev->ring);
s64 time_ns;
__u8 *rxbuf;
int b_sent;
size_t d_size;
/* Ensure the timestamp is 8 byte aligned */
d_size = st->current_mode->numvals*2 + sizeof(s64);
if (d_size % sizeof(s64))
d_size += sizeof(s64) - (d_size % sizeof(s64));
/* Ensure only one copy of this function running at a time */
if (atomic_inc_return(&st->protect_ring) > 1)
return;
/* Monitor mode prevents reading. Whilst not currently implemented
* might as well have this test in here in the meantime as it does
* no harm.
*/
if (st->current_mode->numvals == 0)
return;
rxbuf = kmalloc(d_size, GFP_KERNEL);
if (rxbuf == NULL)
return;
b_sent = i2c_master_recv(st->client,
rxbuf,
st->current_mode->numvals*2);
if (b_sent < 0)
goto done;
time_ns = iio_get_time_ns();
memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
indio_dev->ring->access.store_to(&ring->buf, rxbuf, time_ns);
done:
kfree(rxbuf);
atomic_dec(&st->protect_ring);
}
int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
struct max1363_state *st = indio_dev->dev_data;
int ret = 0;
indio_dev->ring = iio_sw_rb_allocate(indio_dev);
if (!indio_dev->ring) {
ret = -ENOMEM;
goto error_ret;
}
/* Effectively select the ring buffer implementation */
iio_ring_sw_register_funcs(&st->indio_dev->ring->access);
indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
if (indio_dev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_deallocate_sw_rb;
}
/* Configure the polling function called on trigger interrupts */
indio_dev->pollfunc->poll_func_main = &max1363_poll_func_th;
indio_dev->pollfunc->private_data = indio_dev;
/* Ring buffer functions - here trigger setup related */
indio_dev->ring->postenable = &max1363_ring_postenable;
indio_dev->ring->preenable = &max1363_ring_preenable;
indio_dev->ring->predisable = &max1363_ring_predisable;
INIT_WORK(&st->poll_work, &max1363_poll_bh_to_ring);
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_RING_TRIGGERED;
return 0;
error_deallocate_sw_rb:
iio_sw_rb_free(indio_dev->ring);
error_ret:
return ret;
}
void max1363_ring_cleanup(struct iio_dev *indio_dev)
{
/* ensure that the trigger has been detached */
if (indio_dev->trig) {
iio_put_trigger(indio_dev->trig);
iio_trigger_dettach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
kfree(indio_dev->pollfunc);
iio_sw_rb_free(indio_dev->ring);
}
void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
{
iio_ring_buffer_unregister(ring);
};
int max1363_initialize_ring(struct iio_ring_buffer *ring)
{
return iio_ring_buffer_register(ring);
};
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